About a month ago, I was driving along and I heard a rock smack against my windshield... at first I didn't notice a crack until the next day my brother pointed it out on a random drive....the rock hit the top of the windshield, on the black part, and made a rounded L crack about 8 inches long....Basically, I want to know what the best thing to do in this situation???
Impreza wrx 2002 sedan
Thanks for the suggestions!!!

You have to get the windshield replaced. There is no way to repair a crack that size and it will probably continue to grow.
There have been cases of windshields on WRXs that cracked for no apparent reason and were replaced under warranty. However if you heard a rock hit it there will be a visible impact mark so any claim for warranty will be denied.